These types of tablets presses are usually formed as rotary tablets presses in which first the press cups occurs are filled with a readily mixed powder substance, then two press punches with a suitable shape press the powder to form a desired tablet shape and the finished tablet is finally ejected and passed on to a packaging station. The capacity of such rotary tablets presses is very high and is normally between 250,000 to 1,000,000 tablets per hour.
In the field of the manufacture of medicaments, apart from the requirement for an increase in productivity, continuous efforts are being made to improve quality control for increasing the safety of medicaments. The manufacture takes place according to the international standard for good manufacturing practice (Current Good Manufacturing Practice, CGMP), which is specified by the medicament monitoring authorities (for example the US Food and Drug Administration, FDA). For severe infringements against this manufacturing practice, the permission to manufacture medicaments can be withdrawn from a company.
An important part of good manufacturing practice is the physical-chemical and microbiological testing and approval of the finished product. In the course of this testing a number of parameters which describe the quality of the product are tested and compared with specifications. The specifications are laid down either in the approval documentation or in the international pharmacopoeias. Once all specifications are satisfied, the product can be marketed. One of these test parameters is the content of the active ingredient which must be determined quantitatively. Another parameter is the hardness of the tablet. The quantitative determination or the hardness determination is normally performed on a random sample basis and in the form of a destructive test chromatographical methods using fluid or gas and also spectroscopic methods are preferably employed as analysis methods, but they sometimes require preparation of the sample. A destructive mechanical strength analysis is carried out for the hardness measurement. These methods have a relatively high precision, but the speed of analysis is very low. Consequently, these methods are not suitable for supplying a result “in-line”, i.e. immediately during the manufacturing process.
The disadvantage of the random sample batch test is that trends or unusual incidents within the tablet production cannot be detected. There is the risk that tablets are approved as conforming to the specification, although they in reality do not lie within the approval limits. These “out-of-specification” (OOS) products can for example arise due to short-term production problems.
In principle, spectroscopy in the near infrared range is suitable for a continuous check of product flows. The European patent EP-B-0 887 638 for example describes a method and a device for the analysis of the composition of moving tablets or capsules, wherein a near infrared (NIR) radiation source is used and the NIR light reflected from the tablet is detected and examined. However, in this case speeds of only about 50,000 sample analyses per hour could be achieved, which only enables use with relatively slow conveyor belts.
The object of this invention is to provide a tablets press in which an extremely reliable quality control of the manufactured tablets is simultaneously performed.